The present invention relates to a method for controlling a drive unit for a hoist, preferably a hoist for people, where one or more electric motors are used for operating the hoist at different operational sequences for driving/horizontal transport, hoisting/lift and lower in which connection load on the lifting belt as well as the position of the device in a rail system are registered, that the registrations are stored and used for controlling travelling speed, hoist speed, adjustment of the rails depending on the load and the position, that a communication module with data store is used and that a control module is used. The lifting belt may be a lifting apron or a belt constructed of carrier straps.
The invention, moreover, relates to a hoist, preferably a rail-carried hoist for people, where one or more electric motors are used for operating the device at different operational sequences for driving/horizontal transport, hoisting/lift and lower, which device includes means for registering the load as well as the position of the device in a rail system and a control unit arranged to store these registrations and use these to regulate motors for controlling travelling speed, hoist speed, adjustment of rails depending on the load and the position, said hoist includes a communication module and a control module.
In a particular embodiment, the method according to the invention relates to steps where an electric motor is used for lifting the lifting belt which at different operational sequences for lift and lower can be loaded differently or be unloaded, in which connection the load of a person on the lifting belt is registered, that registrations are stored and used for controlling the hoist speed depending on the load.
In a particular embodiment, the hoist according to the invention relates to a system where an electric motor is used for hoisting the lifting belt which at different operational sequences for lift and lower can be loaded at different degrees or be unloaded.
So far, hoists, preferably of the type that has been used as hoist for people, have been able to operate with a well-defined hoist speed irrespective of whether the lifting belt is loaded with a person sitting therein, or not. Such a construction is inconvenient as the hoist speed (and hereby also the lowering speed) will thus always be relatively low compared to the speed that could be used with an unloaded lifting belt.
It will be possible to establish a hoist or a method for operating it, where the hoisting speed/lowering speed is changed manually by the operator. However, such a manual operation can be inconvenient as the risk of maloperation and /or overloading the hoist arises.
From U.S. Pat. No. 5,809,591 a device of the abovementioned type is known, which is provided with resistance regulation for regulating the motor speed and thereby varying the hoist speed. The device is also provided with a strain gauge for registering load of a person which is made a parameter for deciding the hoist speed via a control circuit, as reference data are stored in the control unit and compared to registered data. Due to the way load is registered, this device cannot be used for intelligent controls where the control unit can be used for different operations.